There are two basic requirements for catching game fish or for getting fish to bite when they are not feeding or hungry. One is to have bait such as a fish worm behave naturally in the water in response to currents and water movement. Another is to have the bait look natural. That is it should not be attached to a highly visible line.
These two requirements can be met by using a very light test leader (perhaps two pound test) between the line and the hook. However, if a large fish is hooked, the light test leader will break, and the big ones thus get away or don't get hooked because of a heavy leader that makes bait behave unnaturally and which presents an unnatural look to the fish.
There is no known rig assembly in the art that can permit fishing with a light test leader and converting it to a heavy test leader when a fish is hooked, so that big fish can be caught. One U.S. Pat. No. 1,296,057--Mar. 4, 1919 to W. Ellsworth does provide in a line a shock absorber that will absorb the initial impact of the strike tension to prevent a light line from breaking.